Global population growth necessitates ever-growing agricultural production and keeps the demand for fertilizers high. Two main nutrients, phosphorus and potassium (P/K), can advantageously be provided as potassium phosphates. Numerous agricultural applications require acidic fertilizers, which yield concentrated aqueous solutions without forming precipitates in stock solutions, and which do not leave harmful or useless deposits in the soil, while enhancing the absorption of the nutrients in plants. WO 2007/102159 provides a potassium phosphate-based particulate composition which easily dissolves in water to yield clear acidic solution, the composition being manufactured from phosphoric acid and monopotassium phosphate. Ideally, fertilizers should be available from cost-effective processes, and should have suitable consistency for easy handling. The art still does not provide enough fertilizers with the required characteristics, suitable for all situations, and a need is felt for new large-scale processes for making such fertilizers. It is an object of the present invention to provide a continuous process for manufacturing an easy-to-handle granular acidic P/K fertilizer.
It is also an object of the invention to provide a continuous process for manufacturing an acidic P/K solid fertilizer from commodity chemicals.
It is another object of the invention to provide a solid fertilizer supplying phosphorus and potassium essentially in equiatomic amounts.
It is still another object of the invention to provide a solid fertilizer supplying phosphorus and potassium, the fertilizer being free-flowing and with a low tendency to cake.
It is a still further object of this invention to provide a continuous method for manufacturing a solid, easy-to-handle P/K acidic fertilizer from phosphoric acid and potassium hydroxide.
Other objects and advantages of present invention will appear as description proceeds.